Epilepsy is a chronic neurological disorder defined by a lasting tendency to experience recurrent, unprovoked seizures. A seizure is a brief episode resulting from a sudden, excessive surge of abnormal electrical activity in a group of brain cells. This condition affects people of all ages globally and is among the most common neurological diseases worldwide.
How Epilepsy Spreads
Epilepsy is not a contagious disease, nor is it sexually transmitted. It is classified as a noncommunicable disorder of the brain, meaning it cannot be passed from one person to another through contact. Unlike infections caused by bacteria or viruses, epilepsy is a functional disorder of the central nervous system itself. The condition cannot be transmitted through touch, saliva, blood, or any other bodily fluid. This is because the underlying issue is a predisposition within the brain’s circuitry to generate seizures, not an external pathogen.
Understanding the Origins of Seizures
The causes of epilepsy are diverse, relating to structural changes, metabolic issues, or genetic factors that make the brain susceptible to seizures. Structural causes involve a physical abnormality or injury that creates a seizure-prone environment. Acquired structural causes include severe head trauma or a stroke that restricts oxygen flow to the brain. Brain tumors and certain central nervous system infections, such as meningitis or encephalitis, can also lead to epilepsy.
It is the resulting brain damage, rather than the initial infection itself, that increases the risk of developing recurrent seizures. Developmental structural causes, like focal cortical dysplasia or other congenital brain malformations, are present from birth and involve errors in how the brain was formed.
Metabolic etiologies involve disorders that disrupt the brain’s normal chemical function. These can include inborn errors of metabolism, such as Glucose Transporter Type 1 (GLUT1) deficiency syndrome, which impairs glucose transport into the brain. These metabolic imbalances can alter neuronal excitability, leading to the development of seizures. Despite advances in diagnostics, the cause of epilepsy remains unknown in approximately 50% of cases globally.
Genetic Risk and Inherited Factors
Genetic factors increase susceptibility to epilepsy, separate from acquired brain injury. While many forms are not directly inherited, some individuals carry genetic risk factors. This risk can arise from a single gene mutation, which is often associated with specific, rare epilepsy syndromes.
More commonly, the genetic risk is considered polygenic, involving the cumulative effect of many different common genetic variants. Specialized tools like polygenic risk scores are used to quantify this combined effect, particularly in forms like genetic generalized epilepsy. Having a family history of the disorder suggests an increased likelihood, but it does not guarantee that a person will develop epilepsy, as environmental and structural factors are often necessary for the condition to manifest.